In LTE-Advanced wireless communication system, for FDD MIMO system, in order to obtain higher efficiency of downlink frequency spectrum, the user terminal feeds precoding code words back to the base station for precoding the signals transmitted to the user terminal in the base station. The method is called as implicit feedback, that's, the user terminal determines precoding code words based on the transmission matrix of downlink channels and feed the code words back to the base station. Now, Intel, Huawei companies etc. have already proposed technical scheme of implicit feedback of carrying out first order correlation self-adaption by using the precoding codebook defined in the present standard. “Correlation self-adaption” means modifying the predefined codebook by using the spatial correlation matrix of downlink channels. “Order” means the number of data streams waiting for being transmitted in the base station. But this kind of technical schemes of implicit feedback is only suitable for the one-order condition. For multi-order condition, the system performance deteriorates rapidly. Thus, for multi-order FDD MIMO wireless communication system, a feasible feedback scheme of correlation self-adaption is urgently needed.